Thursday, April 15, 2010

Capsular Contracture

Capsular contracture is a complication of breast implants of all types:  saline, silicone, smooth, textured, etc. 

When the implant is placed, the body forms a capsule of fibrous material around it as it would for any foreign body (ie pace maker, breast implant, etc).  The capsule is initially thin and soft, with little or no effect on the appearance of the breast.  If it remains that way, then it is not called a contracture.

Capsular contracture occurs when the scar tissue or capsule that normally forms around the implant tightens and squeezes the implant. It can happen to one or both of the implants. There are four grades of capsular contracture known as Baker grades.

The Baker grading is as follows

Grade I
breast is normally soft and looks natural

Grade II
breast is a little firm but looks normal

Grade III
breast is firm and looks abnormal

Grade IV
breast is hard, painful, and looks abnormal

Capsular contracture may require reoperation, usually for Grades III and IV, and it may occur again.

The first article listed below looks at the current literature relating to this complication of breast implant surgery, focusing particularly on occurrence rates, risk factors, cause, and treatment modalities to provide the plastic surgeon with an up-to-date review of the current available evidence.

The authors did a literature search of the MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases using three groups of key words --the first relating to the organ involved (breast), the second relating to the surgical procedure performed and related technical issues, and the third relating to the surgical complications. Potentially relevant articles were identified by means of the title and the abstract, and full articles were obtained and assessed in detail.

The authors note:  “Only a few studies have included large enough sample sizes, were conducted in a prospective manner, were adequately randomized, and achieved adequate follow-up periods to obtain a true measure of rates of capsular contraction occurrence.

Reported rates of capsular contractures vary widely, ranging from 1.3 to 30 percent of patients who receive implants.

The longer the implants were in place, the greater the cumulative risk of developing contracture, which would suggest a direct correlation between when the implant is placed and the time to developing contractures.

Approximately 92 percent of contractures occur within the first 12 months following surgery.

A number of parameters seem to influence the occurrence of contractures, including the indications for surgery (breast reconstructions versus cosmetic augmentations), type of prosthesis used (smooth versus textured and saline versus silicone), and positioning of the implant (subglandular versus submuscular).

Currently, Mentor lists the rate of capsular contracture in their patient information brochures (cosmetic not reconstructive) as 9% (Grade III – IV), but note the literature has a wide range of 1.3% to 30%.

Women having reconstructive rather than aesthetic (or cosmetic) augmentation have a higher risk of developing capsular contracture.

Radiotherapy increases the incidence of capsular contractures. Unfortunately, most studies are retrospective in nature and analyze groups of patients who received radiotherapy at variable time points (before, during, or after reconstruction), concomitant chemotherapy, implant positioning or type, and type of contractures reported (only Baker grade 3 or 4 versus all contractures).  All of these factors may partly explain the wide range of reported contractures in the irradiated groups (32- 73%) versus non-irradiated groups (0- 40%).

Numerous studies have looked at shell characteristics (smooth vs textured surface) in regards to contracture rate and tend to find textured surfaces produced a lower incidence of contractures when compared with smooth ones.  

In the first meta-analysis, Barnsley et al. proved the protective effect of textured implants over smooth surfaces (relative risk, 0.19; 95 percent confidence interval, 0.07 to 0.52), with smooth implants showing a five-times greater risk of contracture formation. 

In the second meta-analysis, 235 patients were analyzed, and textured implants were shown to produce fewer capsular contractures when compared with smooth implants at 1 year (relative risk, 4.2; 95 percent confidence interval, 1.6 to 11.0), 3 years (relative risk, 7.3; 95 percent confidence interval, 2.4 to 21.7), and 7 years of follow-up (relative risk, 3.0; 95 percent confidence interval, 0.9 to 10.4).

Only one study showed no significant differences between smooth versus textured implants for the occurrence of capsular contractures.  However, this trial had a Jadad score of 2, indicating a poor methodologic quality with a high degree of variance in the results.

Partial or complete submuscular placement and subfascial positioning are  association with lower rates of capsular contractures.  Many of the articles mentioned are either small or retrospective.

Seckel and Costas retrospectively studied 76 patients (146 breasts) who had undergone partial or total submuscular breast cosmetic augmentation.  No difference was observed between the total and the partial musculofascial coverage for the occurrence of capsular contractures [zero of 35 (0 percent) versus one of 41 (0.02 percent); Fisher's exact test, p = not significant].

Hendricks reviewed 650 patients who had received textured silicone gel implants beneath the pectoralis major muscle, the external oblique muscle, the rectus sheath, and the serratus anterior muscle fascia.  In this study, no cases of Baker grade 3 or 4 capsular contractures were reported.

Ventura and Marcello retrospectively analyzed 100 patients who had received primary breast enlargement with textured implants positioned in the subfascial compartment and found that only two patients (2 percent) experienced Baker grade 2 capsular contractures.

Finally, in a retrospective multicenter study of more than 500 patients, Gutowski et al. found that the use of subglandular positioning of the prosthesis increased the risk of capsular contractures by almost eight times.

It is a nice review of the literature which points out the short comings of our knowledge.

Although it is apparent from the articles studied in this review that a great deal of progress has been made over the past few decades toward elucidating the etiopathogenesis of capsular contractures, the exact nature and contribution of molecular, immunologic, and microbiological factors remain unclear.

Only a few studies have included large enough sample sizes, were conducted in a prospective manner, were adequately randomized, and achieved adequate follow-up periods to obtain a true measure of the rates of capsular contracture occurrence.

Therefore, there is a scant and often inconclusive body of evidence relating to this complication. For example, the contribution of chemotherapy to the occurrence of capsular contractures warrants more thorough investigation.

Likewise, the possibility of preventing this complication by use of experimental drugs needs to be looked at more closely.

Revision surgery remains the only effective treatment option available to us at this time but is limited by its high associated risk of recurrences and complications (hematoma or pneumothorax) when the implant is originally placed in the submuscular position. It is hoped that future studies will focus on attempting to resolve some of the issues highlighted in this review.

 

 

 

REFERENCE

Capsular Contractures: A Systematic Review; Plastic and Reconstructive Surgery. 124(6):1808-1819, December 2009; Araco, Antonino; Caruso, Riccardo; Araco, Francesco; Overton, John; Gravante, Gianpiero

FDA Breast Implant Info, May 2009

1 comment:

Gizabeth Shyder said...

Can't really speak to the literature, but from personal experience of looking at tissue around failed breast implants, I see a lot of capsular contracture. Giant cells. Fibrosis. Even calcification, sometimes. Haven't seen osseus (sp? I need to check, but am too lazy right now) metaplasia in a breast yet, but I'll bet it exists.